1. Field of the Invention
The present invention relates to writing instruments, particularly ball point pens and projecting mechanisms for the writing element.
2. Description of the Prior Art
A problem encountered in the use of ball point pens is that the pens, generally stored in the shirt or coat pocket of the user, tend to mark the coat or pocket when the user stores the pen without retracting the tip of the writting element. In an attempt to solve this problem, pen constructions have been devised to prevent the user from inadvertently storing a pen when the tip of the writing element is exposed.
One such construction is shown in U.S. Pat. No. 2,881,736 issued to N. Zepelovitch. Zepelovitch shows a construction in which the writing element tip is exposed by depressing a rockable clip which is part of the pen casing. A user of the Zepelovitch pen would not be able to store a pen using the clip when the tip of the writing element is exposed.
In another attempt to prevent the inadvertent marking of shirts and coats by a user attempting to store a pen while having the tip of the writing element exposed, Dannebaum in U.S. Pat. No. 3,181,507 shows an automatic retracting pen tip. Dannebaum introduces however, an actuater for projecting the writing element tip which is mechanically complex and therefore impractical for production of such pens on a large scale.